3-6
POWERHEAO
Many, but not all, heads have a thermo-
stat
installed.
In addition
to the
thermo-
stat,
the
engine
may
have
a
thermostat
bypass valve.
These
two items
are
easily
removed,
inspected
and cleaned.
Normally,
if a thermostat
is not
func-
tioning properly,
it is almost always stuck in
the open position.
An engine
operating
at
too low a temperature
is almost
as much a
problem as an engine running too hot.
Therefore,
during a major overhaul, good
shop practice
dictates
to replace
the therm-
ostat
and eliminate
this area
as a possible
problem at a later date.
Lay a piece of fine sandpaper
or emory
paper on a flat
surface
(such as a piece of
glass) with the abrasive
side facing up. With
the
machined
face
of
the
head
on the
sandpaper,
move the head in a circular
mo-
tion to dress the
surface.
This procedure
will also indicate
any "high" or "low" spots.
Check
the
spark
plug
opening/s
to
be
sure
the
threads
are
not
damaged.
Most
marine
dealers
can insert
a heli-co il into a
spark plug opening if the threads
have been
damaged.
On many engines,
a sending unit is in-
stalled
in the head to warn the operator
if
Removing the thermostat
from
the head.
the engine begins to run too hot.
The light
on the dash can be checked
by turning
the
ignition
switch
to the
ON
position,
and then
ground
the
wire to the
sending
unit.
The
light should come on.
If it does not, replace
the bulb and repeat
the test.
3-5
REED
SERVICE
DESCRIPTION
All two-cycle
engines have individual
ig-
nition
and fuel
delivery
for each
cylinder.
This means
the
cylinder
is operating
inde-
pendently
of the others.
The cylinder
con-
sists
of a top seal, the cylinder,
the center
seal,
and the lower seal.
This means
each
cylinder
is completely
sealed
offfrom
the
others.
Therefore,
with
a two-cylinder
power-
head, two sets of reeds are installed,
one for
each cylinder.
These reeds may be installed
on a reed plate or with a reed box, depend-
ing on the
model
engine.
One carburetor
provides fuel to both sets of reeds.
The reed arrangement
operates
in much
the same manner as the reed in a saxophone
Operating
an
engine
without
the
thermostat
and
thermostat
cover
installed
to
check the coolant
water
[low,
Summary of Contents for 4906B 4HP 1969
Page 5: ......
Page 87: ...3 46 POWERHEAD Exploded drawing of a 7 5 hp powerhead 1956 58 with principle parts identified...
Page 88: ...CYLINDER BLOCK 3 47 HEAD GASKET RING...
Page 90: ...CYLINDER BLOCK 3 49 THERMOSTAT EXHAUST COVER The...
Page 137: ...4 46 FUEL LEVER AND LOW SPEED...
Page 153: ...4 62 FUEL Exploded view of a pressure tyoe fuel tank with major parts identified...
Page 157: ...4 66 fUEL...
Page 412: ...A 16 APPENDIX Wire Identification 33 hp with Generator 1965 67...
Page 413: ...APPENDIX A 17 o C...
Page 414: ...Wire Identification 33 hp with Generator 1969 70...
Page 415: ...APPENDIX A 19 Wire Identification 35 hp 1957 59...
Page 416: ...A 20 APPENDIX Wire Identification 40 hp Standard Shift with Generator 1960 66...
Page 417: ...APPENDIX A 21 UJ cc b Wire Identification 40 hp Standard Shift with Generator 1967 68...
Page 419: ...APPENDIX Wire Identification 40 hp Electric Shift with Generator 1961 66 A 23...
Page 420: ...A 24 APPENDIX C 00 Wire Identification 40 hp Electric Shift with Generator 1967 68...
Page 421: ...Wire Identification 40 hp Electric Shift with Generator 1969 70...
Page 422: ...NOTES NUMBERS...
